Got a R4i-B9S from max-console.com yesterday and tested it out. At the beginning my Old 3DS is on firmware v11.6.0-39U, and finally I managed to use R4i-B9S flashcart to hack the console and install 3DS CIA games. Take a look at the following pictures: I installed a US region 3DS CIA as well as a Japan region CIA.

A few things to keep in mind:

Please make sure the first SD card is the original one of your 3DS console, otherwise it will show errors when installing B9S.
At step 5, please remove the magnet first and then hold power button to power off, otherwise the 3DS console can’t be powered off.
At step 12, When it shows “copy successful”, first click A and then click B to return to B9S menu. Only at B9S menu can you press Start button and reboot the system.
Make sure the targeted SD card(for installing games) is authentic TF card, and with enough capacity, otherwise the convert and installation of CIA games may fail